The present invention relates to a seat back support mechanism and more particularly, relates to a seat back support mechanism for supporting the back of a seat intended to be mounted in a vehicle. A preferred seat back support mechanism in accordance with the invention may incorporate a recliner mechanism.
When a vehicle with a conventional seat is involved in a rear impact, the seat may be accelerated with a substantial forward acceleration since the seat is secured to the floor of the vehicle. The posterior and torso of an occupant of the vehicle sitting on the seat will consequently be accelerated, because of the intimate contact between the seat, and the back of the seat, and the posterior and torso of the occupant. The head of the occupant, however, is not in direct contact with the seat and, due to its inertia, will tend to remain stationary. Since the posterior and torso are being accelerated forwardly, this means that effectively the head of the occupant may move rearwardly relative to the torso, thus bending the neck of the occupant. This can cause injury to the occupant.
It is now believed that the risk of injury to an occupant of a vehicle can be diminished if the back of the seat is mounted in such a way that the top part of the seat back can move forwardly to support the head of the occupant and also in such a way that the seat back can subsequently "yield", at least to a predetermined extent, during a rear impact. In this way, the torso of the occupant can be caused to accelerate in a more gradual manner, and the head of the occupant can be supported thus reducing the risk of injury.